Generally, an electronic power steering (EPS) system is a system for securing steering safety of a vehicle, and allows easy handling by supplying power using a motor in a direction in which a driver steers the vehicle.
Such an EPS system may improve a steering performance and a steering feeling by controlling an operation of the motor according to a driving condition unlike a conventional hydraulic power steering (HPS) system.
Specifically, the EPS system controls an inverter to drive the motor according to driving conditions detected by a vehicle speed sensor, a torque angle sensor, a torque sensor, and the like of an electronic control unit (ECU). Accordingly, since a turning safety is secured and a rapid restoring force is provided, the driver may safely drive.
Recently, safety requirements have been increased in the field of vehicles. Accordingly, a technology in which a safety of a vehicle is secured even when some parts (ECU or inverter) of the EPS system are in impossible operation states is required.